This invention relates to an electrically operated lock and, more particularly, to a lock having a rotary latch wheel operable from the inside by manual activation of handle and normally operable from the outside only by use of a correctly coded data combination card.
This invention has particular application to use in buildings, such as hotels, having a large number of rooms required to be locked, and is intended to replace the conventional mechanical lock and key system now in general use. However, it will be understood that the lock of this invention could be employed in any building or enclosure requiring a locked door, such as automobiles.
In typical electronic systems for controlling entrance to protected areas, a door is provided with an electronic lock which responds to a preselected combination code contained on a key which frequently takes the form of a card. If a person wishing to gain entrance through the door inserts the card into a receptacle associated with the lock, the lock circuitry actuates the bolt if the card is correctly coded. Such electrically operated locks have very significant advantages as compared with conventional lock systems, such as the very large number of code combinations which are available on a card of very small size.
However, the mechanical portion of such locks frequently necessitates complex circuitry and mechanical features in order to provide a lock which is mechanically operable from the inside as well as electrically operable from the outside and which takes into consideration the various states which the lock may assume under all conditions of its operation. For example, some locks require a plurality of switches to indicate to the electronics when certain cams or gears are in one position or another, whether the bolt is extended or retracted, and whether the electronics may proceed to the next step. Other such locks require complicated gearing to allow mechanical operation of the lock to override the electrical operation or to initiate the electrical operation.
The invention shown and described herein overcomes these defects by providing a simple mechanical mechanism which may be operated both electrically from outside the door by insertion of an appropriately coded data combination card and mechanically from inside the door by actuating a handle. The requirements for complicated cams or gearing, override mechanisms for motors, complex switch apparatus to indicate the state of the mechanics, and the like are eliminated. In addition, the lock of this invention is reliable, self-contained, has low power requirements, and is inexpensive to construct.